A valve of this type has become known from DE 41 17 445. The prior-art valve comprises a valve housing with a passage channel for the flow medium, in which a cylindrical body with a diaphragm opening, through which the flow medium flows, is inserted in a rotatingly movable manner. The flow cross section of the diaphragm opening is selected, depending on the angular position of the cylindrical body, such that there is a linear relationship between the rotary movement of the cylindrical body and the flow of the flow medium. The prior-art valve is designed for releasing the flow medium to a stationarily operating user.
In certain applications, e.g., in respiration technique, there occur variations in pressure during the operation on the discharge side of the valve, which are caused by inhalation phases and exhalation phases. Thus, a practically unthrottled gas flow is needed during the peaks of the inhalation phases to generate the inhalation pressure needed for respiration, while the pressure shall be reduced as quickly as possible at the time of the transition to the exhalation phase, while the breathing gas being fed in is throttled at the same time.